This invention relates to an inflatable protective spacer structure for reducing the loss of heat from the body of a wearer when subjected to a hostile cold environment. More particularly, the invention relates to an inflatable protective spacer assembly forming a part of an anti-exposure garment which when inflated protects the body of the wearer from excessive loss of body heat in a hostile, cold environment to provide a means for survival.
Anti-exposure garments are used particularly by airmen who are subject to accidental immersion in a cold sea where an excessive loss of body heat would be fatal. Accidental immersion of a person in cold water about 20.degree. C. without immediate availability of rescue presents the lethal consequences of drowning and hypothermia.
Protection from drowning can be provided the airman having a proper flotation device; but hypothermia of airmen downed in a cold hostile environment is more difficult to avoid and is recognized as a major problem particularly in accidental immersion in cold water.
Anti-exposure suits now known in the art are based on three types of design concepts, namely dry with closed-cell foam; dry without closed-cell foam; and wet with closed-cell foam. These suits must be capable of being donned quickly and easily over regular clothing and of course they differ from diving suits since they are typically more bulky and loose fitting to the body.
One of the problems encountered in anti-exposure survival suits is the difficulty of providing for the passage of water vapor produced by the body through the heat insulating barrier that is providing retention of body heat so that the body heat loss is maintained at a minimal level. Also, the heat retention barrier must be of such construction that it does not hinder the movement and ability of the wearer to be mobile and perform manual operations.
Survival suits having foam heat retention spacers or liners not only restrict the manual functions of the body but also must provide additional means for proper dissipation of water vapor from the body of the wearer during use until survival protection is demanded.
The above discussed disadvantages are eliminated by anti-exposure inflatable structures of the present invention by providing an inflatable spacer formed from thin sheets of material that are impervious to the transmission of air therethrough and the sheets of material being capable of being sealed together along common edges and in spaced areas, with the sealed areas having a hole positioned in them to form a plurality of intercommunicating gas retention pockets or chambers which when inflated produce the inflatable spacer.
Advantageously, the inflatable spacer can be formed by heat sealing two thin sheets of water impervious material along contiguous edges and at spaced intervals within the confines of the edges to form the intercommunicating pockets or chambers. The spaced intervals may form a quilt-like configuration which, when an inflating gas is introduced into the closed pockets from a gas supply means that is operatively connected to one wall of the material, produces an inflated spacer that has a quilt-like surface. When the inflated spacer is placed in a garment construction that covers the body, it provides insulation and floatation to a wearer.
The inflatable spacer forming a part of an anti-exposure garment can be constructed so that it covers the body except for the hands, above the lower portion of the neck, and the feet, and has sealed to its marginal edges an outer loose covering layer of a breathable fabric that permits moisture vapor transmission through the fabric so that moisture vapor is transmitted away from the body of a wearer after first passing through the opening in the sealed areas of the spacer. Thus the wearer remains comfortable through dissipation of perspiration and his freedom to perform normal operations and duties is not impaired because there is an absence of bulkiness in this suit.
Advantageously, the inflatable spacer with its outer covering layer of breathable waterproof fabric can have a loose inner covering layer or liner of a lightweight fabric attached to it to form a spacer assembly. The lightweight inner liner aids in donning the spacer assembly.
The inflatable spacer, the water barrier of waterproof breathable fabric, and the lightweight fabric liner all may be bonded to the spacer at the wrist and lower neck areas and to a boot bladder, and have in the front body portion a waterproof closure that permits the donning of the spacer assembly. Such a construction forms a spacer assembly that prevents water from entering between the spacer assembly and that portion of the body of a wearer covered by the spacer assembly.
Thus, there is produced a spacer assembly that provides a flexible, noncompressible insulator garment and water barrier that, under normal wearing conditions, is not bulky or stiff so as to inhibit normal body movement, is light in weight, and provides normal body breathing for maximum comfort; but upon emergency demand, the garment can be converted into a thermal protective and flotation device by inflation to retain the body heat of the wearer to assist in his survival in a hostile cold environment, such as exposure in cold arctic of subarctic seas.
The closest art known to the inventors is the U.S. Pat. to Mauch No. 2,791,168 covering an inflated ventilating cover or blanket construction having two sheets of plastic material sealed together at their marginal edges and at spaced areas with jet holes for passing air from the inflated blanket against the body to provide for continuous air conditioning of the body. The air flowing through the orifice brought into contact with the body is exhausted through openings positioned in the sealed spaced areas. The inflatable spacer assembly of the present invention is an entirely different construction and functions in an entirely different manner since the construction of this invention provides for comfortable wearing of a spacer assembly that is inflatable to provide for the preservation of body heat when survival in a hostile, cold environment is demanded.